DMSO and stem cells differentiation

hello, i have 2 questions:1- i read about differentiation of umbilical cord blood stem cells in to insulin producing cells, and in the methodology they add 1% DMSO to the culture medium with low glucose level then icubate over night or 2 days , after that they change the medium with high glucose medium.i need to know why they add the DMSO?is DMSO playing a role in prevention stem cells differentiation to undesired types?or it enhance stem cells differentiation into insulin producing cells??